The present invention relates to a tiltable joystick pointing device which is suitable for use as a pointing device for video games based on three-dimensional display of objects, and in particular to such a tiltable joystick pointing device which is capable of producing more diverse detector signal contents than was hitherto possible by adding a pull-up and push-down action to the tiltable joystick pointing device.
The contents of the output signal of a conventional tiltable joystick pointing device were strictly two-dimensional, and the pointing directions were confined to a plane perpendicular to the axial line of the joystick. In other words, only the forward, rearward, right, left and oblique directions in a single plane could be indicated by the joystick pointing device. Therefore, when such a pointing device was applied to a video game including three-dimensional display of objects, it was necessary to use a push-button pointing device in combination. The two-dimensional movement of an object can be associated with the corresponding movement of the joystick. The depth-wise movement of an object with respect to the plane of the display device can be associated with the pressing of the pushbutton. Therefore, the user has to use his both hands for individually operating the two different pointing devices, and this has been perceived as quite inconvenient.
To overcome such a problem, it is conceivable to add a push-down and pull-up action to the joystick. This in effect integrally combines a pushbutton pointing device with a joystick pointing device, and would enhance the convenience of the joystick pointing device, allowing the user to operate the device with a single hand.
Typically, the joystick of a joystick pointing device consists of a stick member which is pivotally supported by a mounting base at an intermediate part thereof via a spherical joint, and is normally urged to its upright neutral position by a coil spring coaxially fitted onto the stick member. A plurality of micro-switches are installed in a lower part of the mounting base, around the joystick member, so as to form a tilt direction detector. Selected one or two of the micro-switches are actuated depending on the tilting direction of the joystick member, and a corresponding multi-bit detector signal is produced from the micro-switches.
In such a conventional tiltable joystick pointing device, to allow the joystick member to be axially moveable, it is conceivable to support the spherical joint in an axially moveable manner over a prescribed stroke. However, such an arrangement necessarily requires to keep the relative position between the joystick member and the micro-switches forming the tilt direction detector. This can be accomplished by moving the micro-switches integrally with the joystick member or by providing two sets of micro-switches which are vertically spaced from each other so that the micro-switches may be operated by the joystick member at both the pulled-up and pushed-down positions thereof. In either case, the structure becomes substantially complex, and a significant number of component parts are required so that the cost significantly increases.
In view of such problems of the prior art, a primary object of the present invention is to provide a tiltable joystick pointing device which additionally incorporates a push-down and pull-up action without substantially increasing the complexity of the device.
A second object of the present invention is to provide a tiltable joystick pointing device which is capable of producing an output signal of more versatile contents than was possible with a conventional device.
A third object of the present invention is to provide such a tiltable joystick pointing device which is both economical and durable.
According to the present invention, these and other objects can be accomplished by providing a tiltable joystick pointing device, comprising: a joystick assembly pivotally supported by a base; a first spring assembly for urging the joystick assembly toward an upright neutral position; a tilt direction detector for producing a tilt direction signal corresponding to a tilt direction of the joystick assembly; wherein the joystick assembly comprises a first shaft which is pivotally supported by the base and urged by the first spring assembly into the upright neutral position, a second shaft slidably guided relative to the first shaft so as to be slidable in an axial direction, a second spring assembly for axially urging the second shaft toward an axially neutral position, and a slide direction detector for producing a slide direction signal corresponding to an axial movement of the second shaft.
Thus, by holding the second shaft and tilting the first shaft via the second shaft, a corresponding tilt direction signal is produced from the tilt direction detector in a conventional manner. Additionally, by holding the second shaft and pushing down or pulling down the second shaft relative to the first shaft, a corresponding slide direction signal is produced from the slide direction detector. Thus, by holding the second shaft with a single hand, it is possible to produce both a tilt direction signal and a slide direction signal at will. Furthermore, because the pushing down and pulling up movement of the second shaft is effected while the first shaft is kept stationary with respect to the axial direction, the axial movement of the second shaft would not affect the relative position between the first shaft and the tilt direction detector. Thus, the tilt direction signal can be obtained in a both accurate and reliable manner in spite of the added function of the joystick assembly to produce the slide direction signal. Such push-down and pull-up movements of the second shaft can be conveniently achieved if the upper end of the second shaft extends out of an upper end of the first shaft and carries a knob such as a ball knob thereon.
According to a preferred embodiment of the present invention, the first shaft comprises a hollow tubular member, and the second shaft is slidably received inside the first shaft. Thus, the sliding movement of the second shaft can be accomplished in a both reliable and aesthetically satisfactory manner. To improve the external appearance of the joystick device, a tubular shaft cover may be coaxially attached to the second shaft so as to cover at least an upper end of the first shaft. The length of the shaft cover may be freely selected as desired, and can be used to hide the first shaft from view in any possible arrangement of the first shaft and the second shaft. However, it is particularly favorable when the shaft cover is used to hide the upper end of the first shaft, without regard to the relative position of the second shaft, which telescopically receives the second shaft.
The tilt direction detector can be selected from any known arrangements. It may comprise a plurality of switch elements mounted on a switch mounting plate which is interposed between a lower end of the base and a tilt guide plate. It is also possible to separate the tilt movement of the joystick assembly or the first shaft into rotary movements around two mutually perpendicular axial lines, and produce the desired tilt direction signal from rotary potentiometers, rotary encoders or the likes which can detect such rotary movements.
The switch elements are typically provided with terminal pins which are required to be soldered to a circuit board. In view of the production efficiency and the production cost, it is desirable to eliminate the need to perform such a soldering step during the assembly process, and to allow the soldering step to be performed only after the assembly process is substantially completed. This can be achieved if the tilt direction detector comprises a plurality of switch elements mounted on a tilt guide plate attached to a lower end of the base, and an annular circuit board surrounding the tilt guide plate and having holes for receiving terminal pins extending from the switch elements.
The slide direction detector should be adapted to produce a slide direction detector signal when an axial movement of the second shaft relative to the first shaft exceeds a prescribed stroke in either axial slide direction. For instance, the slide direction detector may comprise a switch holder attached to a lower end of the first shaft, a switch element mounted on the switch holder, and a shaft end member attached to a lower end of the second shaft, the shaft end member being provided with an actuating projection with engages an actuating part of the switch element in response to an axial movement of the second shaft relative to the first shaft. This allows the detection of the axial movement of the second shaft relative to the first shaft without interfering with the tilt movement of the first shaft or the detection of the tilt direction of the first shaft. To accomplish this goal, it is also desirable to keep the second shaft rotationary fast with respect to the first shaft. It can be accomplished in a simple manner if the shaft end member further comprises a stopper arm extending therefrom which is engaged by a vertical guide slot defined in the switch holder for maintaining the second shaft rotationally fast with respect to the first shaft around an axial line thereof.
To produce an accurate and appropriate axial urging force for the second shaft, it is desirable to provide a dedicated spring assembly to produce a well defined spring force instead of relying on the spring force of the return spring of the switch element. Such a spring assembly should be compact enough to be accommodated in a limited space inside the base. Based on such a recognition, the slide direction detector may further comprise an upper spring member compressed between the switch holder and an upper end of the shaft end member so as to urge the second shaft downward with respect to the first shaft, and a lower spring member compressed between a lower end surface of the shaft member and a spring retaining member extending integrally from the switch holder so as to urge the second shaft upward with respect to the first shaft, the second shaft being balanced at a axially neutral position under spring forces of the upper and lower springs.